Title

Author

Degree Type

Thesis

Date of Award

2016

Degree Name

Master of Science

Department

Mechanical Engineering

Major

Mechanical Engineering

First Advisor

SHAN HU

Abstract

Functionalized carbon nanotube (f-CNT) thin films were deposited onto plain nickel foil, nickel foam and nickel nanotube (NiNT) arrays using electrophoretic deposition (EPD to fabricate a CNT-based supercapacitor. A two-dimensional multiphysics model of the EPD process was established to investigate f-CNT particles deposition on nickel substrates with constant voltage and constant current modes. Combined scanning electron microscopy and electrochemical analysis elucidate that the best rate capability is achieved when f-CNT thin films conformally wrap NiNTs and provide the fastest electron transport between active materials and current collectors. The effect of micro and nanostructured current collectors on the rate capability of CNT-nickel supercapacitors was studied by deposition of f-CNT on nickel foil, nickel foam as well as nickel nanotubes (NiNT). 51% capacity retention was calculated for NiNT/f-CNT when scanning rate was increased from 1 to 50 mV/sec in cyclic voltammetry test whereas, nickel foam/f-CNT and nickel foil/f-CNT kept 35% and 30% of their initial capacities in the same test. The specific capacitance of 200 F/g and capacitance retention of 90% after 1000 cycles was obtained for NiNT/f-CNT cell. Frequency analysis demonstrates a higher ability of NiNT/f-CNT to get polarized with the lowest dielectric relaxation time as small as 0.044 sec.